scholarly journals Zn2+-dependent DNAzymes that cleave all combinations of ribonucleotides

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Rika Inomata ◽  
Jing Zhao ◽  
Makoto Miyagishi
Keyword(s):  
In Vitro Selection ◽  
Sequence Similarity ◽  
Sequencing Analysis ◽  
Sequence Specificity ◽  
Rna Sequences ◽  
Catalytic Core ◽  
Highly Active ◽  
Target Rna ◽  
Deep Sequencing Analysis

AbstractAlthough several DNAzymes are known, their utility is limited by a narrow range of substrate specificity. Here, we report the isolation of two zinc-dependent DNAzymes, ZincDz1 and ZincDz2, which exhibit compact catalytic core sequences with highly versatile hydrolysis activity. They were selected through in vitro selection followed by deep sequencing analysis. Despite their sequence similarity, each DNAzyme showed different Zn2+-concentration and pH-dependent reaction profiles, and cleaved the target RNA sequences at different sites. Using various substrate RNA sequences, we found that the cleavage sequence specificity of ZincDz2 and its highly active mutant ZincDz2-v2 to be 5′-rN↓rNrPu-3′. Furthermore, we demonstrated that the designed ZincDz2 could cut microRNA miR-155 at three different sites. These DNAzymes could be useful in a broad range of applications in the fields of medicine and biotechnology.

scholarly journals Encapsulation of ribozymes inside model protocells leads to faster evolutionary adaptation

2021 ◽  
Vol 118 (21) ◽  
pp. e2025054118
Author(s):  
Yei-Chen Lai ◽  
Ziwei Liu ◽  
Irene A. Chen
Keyword(s):  
High Throughput Sequencing ◽  
In Vitro Selection ◽  
Membrane Vesicles ◽  
Bulk Solution ◽  
Evolutionary Adaptation ◽  
Rna Sequences ◽  
Highly Active ◽  
Selective Permeability ◽  
Evolution Of Life

Functional biomolecules, such as RNA, encapsulated inside a protocellular membrane are believed to have comprised a very early, critical stage in the evolution of life, since membrane vesicles allow selective permeability and create a unit of selection enabling cooperative phenotypes. The biophysical environment inside a protocell would differ fundamentally from bulk solution due to the microscopic confinement. However, the effect of the encapsulated environment on ribozyme evolution has not been previously studied experimentally. Here, we examine the effect of encapsulation inside model protocells on the self-aminoacylation activity of tens of thousands of RNA sequences using a high-throughput sequencing assay. We find that encapsulation of these ribozymes generally increases their activity, giving encapsulated sequences an advantage over nonencapsulated sequences in an amphiphile-rich environment. In addition, highly active ribozymes benefit disproportionately more from encapsulation. The asymmetry in fitness gain broadens the distribution of fitness in the system. Consistent with Fisher’s fundamental theorem of natural selection, encapsulation therefore leads to faster adaptation when the RNAs are encapsulated inside a protocell during in vitro selection. Thus, protocells would not only provide a compartmentalization function but also promote activity and evolutionary adaptation during the origin of life.

In vitro selection of RNA sequences capable of mediating the formation of iron oxide nanoparticles

2009 ◽  
Vol 19 (44) ◽  
pp. 8320 ◽  
Author(s):  
Carly J. Carter ◽  
Magda Dolska ◽  
Alina Owczarek ◽  
Christopher J. Ackerson ◽  
Bruce E. Eaton ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
In Vitro Selection ◽  
Oxide Nanoparticles ◽  
Rna Sequences ◽  
Selection Of

scholarly journals In vitro selection of ribozyme ligases that use prebiotically plausible 2-aminoimidazole–activated substrates

2020 ◽  
Vol 117 (11) ◽  
pp. 5741-5748 ◽  
Author(s):  
Travis Walton ◽  
Saurja DasGupta ◽  
Daniel Duzdevich ◽  
Seung Soo Oh ◽  
Jack W. Szostak
Keyword(s):  
Origin Of Life ◽  
In Vitro Selection ◽  
Random Sequence ◽  
Bond Formation ◽  
Rna Sequences ◽  
Phosphodiester Bond ◽  
Complex Protein ◽  
The Origin Of Life ◽  
Group 2

The hypothesized central role of RNA in the origin of life suggests that RNA propagation predated the advent of complex protein enzymes. A critical step of RNA replication is the template-directed synthesis of a complementary strand. Two experimental approaches have been extensively explored in the pursuit of demonstrating protein-free RNA synthesis: template-directed nonenzymatic RNA polymerization using intrinsically reactive monomers and ribozyme-catalyzed polymerization using more stable substrates such as biological 5′-triphosphates. Despite significant progress in both approaches in recent years, the assembly and copying of functional RNA sequences under prebiotic conditions remains a challenge. Here, we explore an alternative approach to RNA-templated RNA copying that combines ribozyme catalysis with RNA substrates activated with a prebiotically plausible leaving group, 2-aminoimidazole (2AI). We applied in vitro selection to identify ligase ribozymes that catalyze phosphodiester bond formation between a template-bound primer and a phosphor-imidazolide–activated oligomer. Sequencing revealed the progressive enrichment of 10 abundant sequences from a random sequence pool. Ligase activity was detected in all 10 RNA sequences; all required activation of the ligator with 2AI and generated a 3′-5′ phosphodiester bond. We propose that ribozyme catalysis of phosphodiester bond formation using intrinsically reactive RNA substrates, such as imidazolides, could have been an evolutionary step connecting purely nonenzymatic to ribozyme-catalyzed RNA template copying during the origin of life.

scholarly journals Integrated analysis of RNA-binding protein complexes using in vitro selection and high-throughput sequencing and sequence specificity landscapes (SEQRS)

Methods ◽  
2017 ◽  
Vol 118-119 ◽  
pp. 171-181 ◽  
Author(s):  
Tzu-Fang Lou ◽  
Chase A. Weidmann ◽  
Jordan Killingsworth ◽  
Traci M. Tanaka Hall ◽  
Aaron C. Goldstrohm ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Sequencing ◽  
In Vitro Selection ◽  
Rna Binding ◽  
Protein Complexes ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Integrated Analysis ◽  
Sequence Specificity

scholarly journals A crystal structure of a collaborative RNA regulatory complex reveals mechanisms to refine target specificity

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Chen Qiu ◽  
Vandita D Bhat ◽  
Sanjana Rajeev ◽  
Chi Zhang ◽  
Alexa E Lasley ◽  
...  
Keyword(s):  
Crystal Structure ◽  
In Vitro Selection ◽  
Rna Binding ◽  
Sequence Specificity ◽  
Binding Assays ◽  
Regulatory Complex ◽  
Rna Motif ◽  
Rna Complex ◽  
Motif Recognition

In the Caenorhabditis elegans germline, fem-3 Binding Factor (FBF) partners with LST-1 to maintain stem cells. A crystal structure of an FBF-2/LST-1/RNA complex revealed that FBF-2 recognizes a short RNA motif different from the characteristic 9-nt FBF binding element, and compact motif recognition coincided with curvature changes in the FBF-2 scaffold. Previously, we engineered FBF-2 to favor recognition of shorter RNA motifs without curvature change (Bhat et al., 2019). In vitro selection of RNAs bound by FBF-2 suggested sequence specificity in the central region of the compact element. This bias, reflected in the crystal structure, was validated in RNA-binding assays. FBF-2 has the intrinsic ability to bind to this shorter motif. LST-1 weakens FBF-2 binding affinity for short and long motifs, which may increase target selectivity. Our findings highlight the role of FBF scaffold flexibility in RNA recognition and suggest a new mechanism by which protein partners refine target site selection.

scholarly journals Identification of BCL-XL as highly active survival factor and promising therapeutic target in colorectal cancer

2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Anna-Lena Scherr ◽  
Andreas Mock ◽  
Georg Gdynia ◽  
Nathalie Schmitt ◽  
Christoph E. Heilig ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Ex Vivo ◽  
Combined Treatment ◽  
Therapy Resistance ◽  
Sequencing Analysis ◽  
Protein Activity ◽  
Highly Active ◽  
Promising Therapeutic Target ◽  
Induced Apoptosis

Abstract Since metastatic colorectal cancer (CRC) is a leading cause of cancer-related death, therapeutic approaches overcoming primary and acquired therapy resistance are an urgent medical need. In this study, the efficacy and toxicity of high-affinity inhibitors targeting antiapoptotic BCL-2 proteins (BCL-2, BCL-XL, and MCL-1) were evaluated. By RNA sequencing analysis of a pan-cancer cohort comprising >1500 patients and subsequent prediction of protein activity, BCL-XL was identified as the only antiapoptotic BCL-2 protein that is overactivated in CRC. Consistently, pharmacologic and genetic inhibition of BCL-XL induced apoptosis in human CRC cell lines. In a combined treatment approach, targeting BCL-XL augmented the efficacy of chemotherapy in vitro, in a murine CRC model, and in human ex vivo derived CRC tissue cultures. Collectively, these data show that targeting of BCL-XL is efficient and safe in preclinical CRC models, observations that pave the way for clinical translation.

scholarly journals A crucial RNA-binding lysine residue in the Nab3 RRM domain undergoes SET1 and SET3-responsive methylation

2020 ◽  
Vol 48 (6) ◽  
pp. 2897-2911 ◽  
Author(s):  
Kwan Yin Lee ◽  
Anand Chopra ◽  
Giovanni L Burke ◽  
Ziyan Chen ◽  
Jack F Greenblatt ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Recognition ◽  
Rna Sequences ◽  
Rna Recognition Motifs ◽  
Rrm Domain ◽  
Lysine Residues ◽  
Recognition Motifs ◽  
Nascent Transcripts ◽  
Target Rna

Abstract The Nrd1–Nab3–Sen1 (NNS) complex integrates molecular cues to direct termination of noncoding transcription in budding yeast. NNS is positively regulated by histone methylation as well as through Nrd1 binding to the initiating form of RNA PolII. These cues collaborate with Nrd1 and Nab3 binding to target RNA sequences in nascent transcripts through their RRM RNA recognition motifs. In this study, we identify nine lysine residues distributed amongst Nrd1, Nab3 and Sen1 that are methylated, suggesting novel molecular inputs for NNS regulation. We identify mono-methylation of one these residues (Nab3-K363me1) as being partly dependent on the H3K4 methyltransferase, Set1, a known regulator of NNS function. Moreover, the accumulation of Nab3-K363me1 is essentially abolished in strains lacking SET3, a SET domain containing protein that is positively regulated by H3K4 methylation. Nab3-K363 resides within its RRM and physically contacts target RNA. Mutation of Nab3-K363 to arginine (Nab3-K363R) decreases RNA binding of the Nab3 RRM in vitro and causes transcription termination defects and slow growth. These findings identify SET3 as a potential contextual regulator of Nab3 function through its role in methylation of Nab3-K363. Consistent with this hypothesis, we report that SET3 exhibits genetic activation of NAB3 that is observed in a sensitized context.

scholarly journals Failure to maintain full-term pregnancies in pig carrying klotho monoallelic knockout fetuses

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sanghoon Lee ◽  
Min Hee Jung ◽  
Kilyoung Song ◽  
Jun-Xue Jin ◽  
Anukul Taweechaipaisankul ◽  
...  
Keyword(s):  
Cell Lines ◽  
Full Term ◽  
Sequencing Analysis ◽  
Limited Information ◽  
Wild Type ◽  
Fetal Fibroblasts ◽  
Klotho Protein ◽  
Large Animals ◽  
Deep Sequencing Analysis

Abstract Background Small animals that show a deficiency in klotho exhibit extremely shortened life span with multiple aging-like phenotypes. However, limited information is available on the function of klotho in large animals such as pigs. Results In an attempt to produce klotho knockout pigs, an sgRNA specific for klotho (targeting exon 3) was designed and Cas9-sgRNA ribonucleoproteins were transfected into porcine fibroblasts. Transfected fibroblasts were cultured for one to 2 days and then directly used for nuclear transfer without selection. The cloned embryos were cultured in vitro for 7 days and analyzed to detect modifications of the klotho gene by both T7E1 and deep sequencing analysis. Modification succeeded in 13 of 20 blastocysts (65%), 8 of which (40.0%) were monoallelic modifications and 5 (25.0%) were biallelic modifications. Based on high mutation rates in blastocysts, we transferred the cloned embryos to 5 recipient pigs; 1 recipient was pregnant and 16 fetuses were recovered at Day 28 post transfer. Of the 16 fetuses, 9 were resorbing and 7 were viable. Four of 9 (44.4%) resorbing fetuses and 3 of the 7 (42.9%) viable fetuses had monoallelic modifications. Thus, 3 klotho monoallelic knockout cell lines were established by primary culture. A total of 2088 cloned embryos reconstructed with 2 frame-shifted cell lines were transferred to 11 synchronized recipients. Of the recipients, 7 of 11 eleven (63.6%) became pregnant. However, none of the pregnancies was maintained to term. To discover why klotho monoallelic knockout fetuses were aborted, expression of aging- and apoptosis-related genes and klotho protein in placentas from klotho monoallelic knockout and wild-type fetuses was investigated. Placentas from klotho monoallelic knockout fetuses showed negatively changed expression of aging- and apoptosis-related genes with lower relative expression of klotho protein. These results indicated that the reason why klotho monoallelic knockout fetuses were not maintained to term was possibly due to decreased klotho expression in placentas, negatively affecting aging- and apoptosis-related genes. Conclusions Klotho monoallelic knockout porcine fetal fibroblasts were successfully established. However, pigs carrying klotho monoallelic knockout fetuses failed to maintain full-term pregnancy and a decrease in klotho expression in placenta likely leads to pregnancy loss.

scholarly journals Assessing the in vitro resistance development in Enterovirus 71 in the context of combination antiviral treatment

2020 ◽  
Author(s):  
Kristina Lanko ◽  
Chenyan Shi ◽  
Shivaprasad Patil ◽  
Leen Delang ◽  
Jelle Matthijnssens ◽  
...  
Keyword(s):  
Antiviral Treatment ◽  
Enterovirus 71 ◽  
Sequencing Analysis ◽  
Resistance Development ◽  
Development Of Resistance ◽  
Enterovirus A71 ◽  
Polymerase Inhibitor ◽  
Direct Acting ◽  
Deep Sequencing Analysis

AbstractThere are currently no antivirals available to treat infection with enterovirus A71 (EV-A71) or any other enterovirus. The extensively studied capsid binders select rapidly for drug-resistant variants. We here explore whether the combination of two direct-acting enterovirus inhibitors with a different mechanism of action may delay or prevent resistance development to the capsid binders. To that end, the in vitro dynamics of resistance development to the capsid binder pirodavir was studied either alone or in combination with (i) a viral 2C-targeting compound (SMSK_0213), (ii) a viral 3C-protease inhibitor (rupintrivir) or (iii) a viral RNA-dependent RNA polymerase (RdRp) inhibitor [7-deaza-2’C-methyladenosine (7DMA)]. We demonstrate that combining pirodavir with either rupintrivir or the nucleoside analogue 7DMA delays the development of resistance to pirodavir and that no resistance to the protease or polymerase inhibitor develops. The combination of pirodavir with the 2C inhibitor results in a double-resistant virus population. The deep sequencing analysis of resistant populations revealed that even though resistant mutations are present in less than 30% of the population, this still provides the resistant phenotype.

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